A jacking frame is a support structure, typically used in offshore drilling operations, which supports a coiled tubing injector and pressure-control equipment attached thereto, such as a blow out preventer. Typical offshore jacking frame structures include a square based frame having single or multiple stackable square frames. These square frames are used to provide the height needed to deploy coiled tubing tools into a wellhead, and to install the blow out preventer units to the coiled tubing injector above the wellhead.
Typically the uppermost box of the jacking frame is capable of lifting the coiled tubing injector head 2-8 feet vertically to compensate for movements of the offshore platform. Such a jacking frame is commonly referred to as a compensated jacking frame, or a heave compensated jacking frame. When needed, additional box sections can be added to increase the overall, or stack-up, height of the jacking frame.
The above described jacking frames are large, bulky structures that tend to take up a considerable amount of space. As such, these jacking frames are too large to be mounted within the mast structure of a derrick, and instead are mounted externally to the derrick, thus occupying a large amount of platform area. Accordingly, a need exists for an improved structure for use as a jacking frame.